Ozone air quality during the 2008 Beijing Olympics: effectiveness of emission restrictions 1Department of Environmental Science and Engineering and State Key Joint Laboratory of Environment Simulation and Pollution, Tsinghua University, Beijing, China
2Department of Earth and Planetary Sciences and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
3Harvard China Project and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
Received: 07 April 2009 – Published in Atmos. Chem. Phys. Discuss.: 20 April 2009 Abstract. A series of aggressive measures was launched by the Chinese government to
reduce pollutant emissions from Beijing and surrounding areas during the
Olympic Games. Observations at Miyun, a rural site 100 km downwind of the
Beijing urban center, show significant decreases in concentrations of
O3, CO, NOy, and SO2 during August 2008, relative to August 2006–2007.
The mean daytime mixing ratio of O3 was lower by about 15 ppbv,
reduced to 50 ppbv, in August 2008. The relative reductions in daytime
SO2, CO, and NOy were 61%, 25%, and 21%, respectively.
Changes in SO2 and in species correlations from 2007 to 2008 indicate
that emissions of SO2, CO, and NOx were reduced at least by
60%, 32%, and 36%, respectively, during the Olympics. Analysis of
meteorological conditions and interpretation of observations using a
chemical transport model suggest that although the day-to-day variability in
ozone is driven mostly by meteorology, the reduction in emissions of ozone
precursors associated with the Olympic Games had a significant contribution
to the observed decrease in O3 during August 2008, accounting for
80% of the O3 reduction for the month as a whole and 45% during
the Olympics Period (8–24 August). The model predicts that emission
restrictions such as those implemented during the Olympics can affect
O3 far beyond the Beijing urban area, resulting in reductions in
boundary layer O3 of 2–10 ppbv over a large region of the North China
Plain and Northeastern China.
Revised: 11 July 2009 – Accepted: 20 July 2009 – Published: 29 July 2009
Citation: Wang, Y., Hao, J., McElroy, M. B., Munger, J. W., Ma, H., Chen, D., and Nielsen, C. P.: Ozone air quality during the 2008 Beijing Olympics: effectiveness of emission restrictions, Atmos. Chem. Phys., 9, 5237-5251, doi:10.5194/acp-9-5237-2009, 2009.